SRS - Technical Centre: Helpful Hints

1. Follow the instructions from your investment powder supplier as to the mixing procedures for the investment powder.

2. Store the investment powder in a cool dry area. Reseal the bag or drum after use.

3. Keep the investment mixing area and equipment clean to avoid contamination with old set investment as this will effect the setting time of the mix.

DIRTY	CLEAN

4. Use a filter on your water line if you are in an area with sediments within the water supply.

5. Always follow the recommended powder water ratio's and measure both the powder and water accurately. Incorrect ratio's can cause weak investment moulds resulting in cracks, breakdown and poor surface finish.

6. Measure the temperature of the water being used; the recommended temperature is 22 degrees Celsius. This can be varied in hot or cold climates to maintain a constant set time. Colder water will extend the work time; warm water will shorten the work time.

7. Time all mixing, vacuuming and vibrating cycles to ensure that a uniform result in investment making. The successful process can then be followed each time and give consistent results. If the investing is extended past the work time, fins and flashing may occur. If the investment is not mixed, vacuumed or vibrated enough, bubbles or nodules might appear on the casting.

8. Let the flasks stand for a minimum of 2 hours before removing the rubber bases. Rough handling can cause pieces of investment to break off, leading to inclusions in the casting.

EARLY	CORRECT

9. Make sure the burn out oven is cool before loading the flasks for burnout.

10. Check the vacuum is working on the investing machine and change the oil at regular intervals.

View other helpful hints online or download (Acrobat Reader PDF) versions by selecting relevant links below:

HELPFUL HINTS

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